Navigation systems that guide the movement of vehicles, bicycles and persons while moving together with them are now in widespread use.
A currently popular navigation system is configured to show a map containing roads on a display at a position of, for example, the dashboard in a vehicle or the like where the driver can view, and guide the driver to a destination by showing a route to the destination on the map. Namely, a conventional navigation system is configured to show a map, and thereby the driver recognizes a route to a destination, an intersection at which the vehicle will make a turn and the like, which are based on a relationship among roads, facilities or the like on the map. For example, Patent Document 1 and Patent Document 2 listed below are cited as prior art documents related to such conventional navigation systems.
In a conventional navigation system as described above, when viewing the display at a position of the dashboard, the driver needs to move his or her line of sight from the front to a position at which the display is viewable. Some people point out a safety problem with regard to this movement of line of sight.
Therefore, in recent years, instead of a display to be provided on a dashboard as described above, navigation systems equipped with a so-called head-up display (referred to below as simply an “HUD”) have been developed. Such a navigation system guides the driver by causing the HUD to apply special treatment to a part of the front window which the diver views upon driving and projecting/showing necessary information to or on this part, such as information regarding a right or left turn. Moreover, navigation systems equipped with a so-called head mounted display (referred to below as simply an “HMD”) have also been developed. An HMD is embedded in a helmet that the driver wears on his or her head, and shows a map and the like. Navigation systems equipped with such an HUD or an HMD are believed to be appropriate in terms of safety, because drivers no longer need to move their lines of sight from the front in order to visually recognize guide information.